This invention relates to O-ring seals, and more specifically to O-rings of elastomeric material that are provided with a particular slot construction.
Seals in the form of O-rings made of rubber or rubber-like materials such as elastomers are well known. They are circular in cross section. They generally fit into rectangular cross section cavities of slightly smaller dimensions. This causes deformation of the ring by forces exerted at the tangential contacts of the ring with the flat walls of the cavity. The deformation provides wide contacts for enhanced sealing. As the ring deforms, material is forced from the circular section. The forces involved increase exponentially with the degree of deformation. Consequently, the dimensions of the cavity must be carefully controlled. For this reason, the sealing cavities generally must be precision machined, rather than economically cast or molded. In dynamic sealing situations, there is a tendency for the ring to roll. Another problem is the tendency for the ring to absorb fluids, such as lubricants. As the ring absorbs fluid, it will swell. This may create excessive friction, heating the ring and even freezing operation.
U.S. Pat. No. 2,521,248 to Parker discloses O-rings with V shaped slots that do not extend beyond the center of the cross section to accommodate swelling and prevent rolling in dynamic sealing situations.
U.S. Pat. No. 2,729,478 to Chambers discloses an O-ring made of tough, substantially nondeformable material such as xe2x80x9cTeflonxe2x80x9d that is lubricious and resistant to lubricant absorption.
It is accordingly an object of the invention to provide an O-ring that will be resistant to rolling. It is another object to provide an O-ring that will better tolerate the swelling from absorption of lubricant. It is yet another object to provide an O-ring that will be able to accommodate to cavities of wider tolerance. It is yet another object to provide an O-ring that seals effectively with reduced friction, and for low pressure dynamic applications. The O-ring of the invention comprises an elastomeric composition having a radial axial cross section that is substantially the shape of a circle. A concentric slot extends at right angles to the plane of the ring from the surface of the ring to a point past the center of the circle. This structure enables the ring to conform to a confined space by bending and closing the slot.
These and other objects, features, and advantages of the invention will become more apparent when the detailed description is studied in conjunction with the drawings in which like elements are designated by like reference characters in the various drawing figures.